Journal of the Arkansas Academy of Science
Volume 70 Article 14
2016 Age and Correlation of the Moorefield hS ale (Upper Mississippian) in its Type Area, Northeastern Arkansas O. Dalu University of Arkansas, Fayetteville
W. S. Coffey Devon Energy
W. L. Manger University of Arkansas, Fayetteville, [email protected]
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Recommended Citation Dalu, O.; Coffey, W. S.; and Manger, W. L. (2016) "Age and Correlation of the Moorefield Shale (Upper Mississippian) in its Type Area, Northeastern Arkansas," Journal of the Arkansas Academy of Science: Vol. 70 , Article 14. Available at: http://scholarworks.uark.edu/jaas/vol70/iss1/14
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Age and Correlation of the Moorefield Shale (Upper Mississippian) in its Type Area, Northeastern Arkansas
O. Dalu1, W.S. Coffey2, and W.L. Manger1
1Department of Geosciences, University of Arkansas, Fayetteville 2Devon Energy, Oklahoma City, Oklahoma
Correspondence: [email protected]
Running Title: Age and Correlation of the Moorefield Shale (Upper Mississippian), Northeastern Arkansas
Abstract biostratigraphically useful fossils, likely extends to at least the middle Chesterian. Thus, the bulk of the The name Moorefield was proposed by Adams and Moorefield formation represents the Chesterian, not the Ulrich (1904) for exposures of gray to brown, Meramecian Series. This age assignment is phosphatic shale with a basal limestone, overlying the complicated further by the reduction of the Lower Mississippian Boone Formation, and underlying lithostratigraphic units comprising the type the Upper Mississippian Batesville Sandstone, in the Meramecian Series (Lane and Brenckle 2005), and a vicinity of Moorefield, Independence County, lack of ammonoid assemblages in its type area, St. northeastern Arkansas. Gordon (1944) 1) restricted the Louis County, Missouri. name Moorefield to the lower limestone-bearing interval, 2) applied a new name, Ruddell, to the History of Moorefield Stratigraphic Investigations succeeding shale section that comprises the bulk of the interval, with a type area near Moorefield, and 3) The earliest record of systematic geological interpreted the interval contacts as unconformities. observations in northern Arkansas was by David Dale The name Ruddell was used for the revised Geological Owen, in a volume treating the northern counties Map of Arkansas (1993), but later publications by the published in 1858. Owen was appointed state Arkansas Geological Survey and other sources refer geologist by Governor E. N. Conway on April 20, the entire interval to the Moorefield Shale, and report a 1857. He arrived in Arkansas in early October, 1857, maximum thickness of 91.44 m. (300 feet). and began working in the northeastern corner, Greene Age assignments for the Moorefield Shale are County, proceeding westward across the northern two based almost entirely on ammonoid cephalopods (e.g. tiers of counties. The work was done on horseback and Gordon 1965, Saunders et al. 1977, Korn and Titus supported by horse-drawn wagons, focusing on 2011). Brachiopods (e.g. Girty 1911) have provided a potential economic mineral deposits. Independence supporting role, but never to the precision of the County was the fourth county visited, and Owen’s ammonoids. Initially, Gordon (1965) recognized two descriptions comprise eight pages of his first 256 page ammonoid zones and four subzones through all the report (Owen 1858). Owen recognized the Moorefield, except the base. Korn and Titus (2011) Archimedes Limestone (=Pitkin Limestone), and what reexamined Gordon’s published ammonoid is likely the Batesville Sandstone overlying a 9.14 m. assemblages, and made additional collections from the (30 foot) section of brown-black shale with limestone type Moorefield. They recognized only two intervals that is probably the Moorefield Shale, but did Moorefield ammonoid zones: the lower Goniatites not name either interval. The northern counties report eganensis - Girtyoceras welleri zone, succeeded by the included at least some description of the geology of 18 upper Goniatites multiliratus zone concentrated near counties. It was followed by a second report on the the middle of the interval. The best age assignment for middle and southern counties, published in 1860 that these abundant, middle Moorefield ammonoid concluded his survey of Arkansas. Owen died on assemblages is to the lower Chesterian Series (Korn November 13, 1860. and Titus 2011). The unfossiliferous lower Moorefield During Reconstruction, the Arkansas legislature Shale spans the Meramecian-Chesterian boundary. appointed a series of state geologists and funded some The upper section, above the ammonoid occurrences, geological work, but it was not until January 19, 1887 but also barren of ammonoids, and other that an Arkansas Geological Survey was organized, Journal of the Arkansas Academy of Science, Vol. 70, 2016 77 Published by Arkansas Academy of Science, 2016 77 Journal of the Arkansas Academy of Science, Vol. 70 [2016], Art. 14 O. Dalu, W.S. Coffey, and W.L. Manger
with J. C. Branner as State Geologist, and a staff of the Moorefield Shale in 1911. He reviewed the young geologists that would become well-known in the lithostratigraphic and chronostratigraphic age profession. Again, the Survey was charged with an assignments for the Moorefield, although he retained assessment of potential economic mineral occurrences, the name “Spring Creek Limestone” of Williams some of which had been identified by Owen (1858, (1895), even though he knew it was preoccupied, 1860). In particular, the Survey was to evaluate the arguing that its chronostratigraphic importance validity of a gold rush that had developed in the mid- outweighed an application of priority (Fig. 3). Girty 1880s in the Ouachita Mountain region. In fact, the (1911) was equivocal about age assignments for the first publication of the new geological survey authored interval, but concluded that the lower portion of the by T. B. Comstock (1888) exposed the Ouachita gold section, the Spring Creek Limestone, was Meramecian, rush as a scam. On a brighter side, the Branner Survey based mainly on brachiopods. He correlated the higher hired the well-known geologist Richard Alexander portions of the Moorefield Shale with the Kaskaskia Fullerton Penrose Jr. to investigate manganese Limestone/Formation/ Group of Hall, 1857, which occurrences in northeastern Arkansas, particularly the became the Chesterian Group of Worthen (1860), and area surrounding Batesville, Independence County, that later the Chesterian Series of Worthen (1866). proved to be a legitimate resource. Mackenzie Gordon Jr. (1944), U.S. Geological The Penrose report (1891) was the first volume Survey, reviewed the stratigraphic relationships of the published by the Arkansas Geological Survey for work in 1890. It provided a stratigraphic column (Fig. 1), but from the current perspective, there are several problems. Most significantly, Penrose shows the Fayetteville Shale lying between the Boone Chert and the Batesville Sandstone in Independence County (Fig. 1). In fact, that shale has become known as the Moorefield Shale, while the Fayetteville Shale lies above the Batesville Sandstone. Penrose was a little closer to current thinking by assigning the Boone Chert and what would be Moorefield Shale to the Osagean Group, now Osagean Series, while the Batesville and Fayetteville intervals are assigned to the Genevieve or Boston Group, historically regarded as Meramecian (Fig. 1). Currently, the Fayetteville Shale is regarded as belonging to the Upper Chesterian Series. The accepted naming and lithostratigraphic correlation of the Moorefield and associated units reflects the work of Adams and Ulrich on the lead and zinc deposits in northern Arkansas, published by the U.S. Geological Survey in 1904 (Fig. 2). Adams and Ulrich (1904) moved the Fayetteville to its proper position, and named the Moorefield Shale, indicating that it succeeded the underlying Boone Limestone unconformably, and was conformably overlain by the Batesville Sandstone (Fig. 2). They also included the Spring Creek Limestone Member at the base of the Moorefield that had been proposed by H.S Williams (1895). Unfortunately, the name Spring Creek was preoccupied by a unit of that name in the Pennsylvanian succession of Texas named by Noah Drake (1893), ironically the third chairman of the Department of Geology at the University of Arkansas. George H. Girty, a well-known U.S. Geological Survey Fig. 1: Stratigraphic Section in the Vicinity of Batesville, paleontologist, published a description of the fauna of Independence County (Penrose, 1891). Journal of the Arkansas Academy of Science, Vol. 70, 2016 78 http://scholarworks.uark.edu/jaas/vol70/iss1/14 78 Journal of the Arkansas Academy of Science, Vol. 70 [2016], Art. 14 Age and Correlation of the Moorefield Shale (Upper Mississippian), Northeastern Arkansas
Fig. 3: Review of Lithostratigraphic Nomenclature Applied to the Moorefield Interval in Northeastern Arkansas (Girty 1911)
Fig. 2: Stratigraphic Section for the Lead and Zinc Deposits in Northern Arkansas (Ulrich, in Adams 1904). Current Age Assignment of the Moorefield Interval, Northern Arkansas
Moorefield interval in the Batesville Manganese Current age assignment for the Moorefield Shale is District, Independence County. He restricted use of based almost entirely on ammonoid cephalopods (e.g. the name Moorefield to the black, calcareous shale and Gordon 1965, Saunders et al. 1977, Korn and Titus limestone at the base of the interval, previously called 2011). Brachiopods (e.g. Girty 1911) have provided a the Spring Creek Limestone, and proposed the name supporting role, but never to the precision of the Ruddell to designate the succeeding shale interval that ammonoids, and neither Moorefield conodonts nor comprised most of the section. Gordon (1944) palynomorphs have ever been evaluated. Korn and concluded that the restricted Moorefield correlated to Titus (2011) reexamined Gordon’s ammonoid the St. Louis Limestone, while the Ruddell was assemblages, and made additional collections from the equivalent to the St. Genevieve Limestone, both type Moorefield. They recognized two Moorefield assigned at the time to the Meramecian of the type ammonoid zones: the lower Goniatites eganensis - Mississippi Valley section. That lithostratigraphic Girtyoceras welleri zone, succeeded by the upper assessment continued into the 1960s, until Gordon Goniatites multiliratus zone. The best age assignment (1965) published an extensive description of the of these abundant Moorefield ammonoid assemblages Carboniferous ammonoid assemblages of Arkansas occurring toward the middle portion of that that he organized into zones and correlated to the type stratigraphic interval is to the lower Chesterian Series Mississippi Valley succession (Fig. 4). In this revision, (Korn and Titus 2011). Thus, the lower Moorefield Gordon (1965) regarded the Ruddell as spanning the Shale, as a low-stand wedge, must certainly span the Meramecian-Chesterian boundary, and interpreted the Osagean-Meramecian boundary, even though barren. Moorefield lower and upper contacts as unconformities The upper section, also barren of ammonoids, and throughout most of their extent (Fig. 4). other biostratigraphically useful fossils, is unstudied,
Journal of the Arkansas Academy of Science, Vol. 70, 2016 79 Published by Arkansas Academy of Science, 2016 79 Journal of the Arkansas Academy of Science, Vol. 70 [2016], Art. 14 O. Dalu, W.S. Coffey, and W.L. Manger
Fig. 4: Biostratigraphic and Chronostratigraphic Correlations for the Moorefield-Ruddell Interval, Northeastern Arkansas (Gordon 1965).
but is no older than middle Chesterian. Therefore, the contact of the lower and upper members of the Warsaw Moorefield most likely spans the interval from early Shale. They also lowered the top of the Meramecian Meramecian to at least the middle Chesterian; the bulk Series to the top of the St. Louis Limestone. Thus, the of the formation represents the Chesterian, not the Ste. Genevieve, historically regarded as Meramecian, Meramecian, Series. and which they contend is not present in the type area of the Meramecian Series, becomes part of the Duration of the Meramecian Series Chesterian Series. Consequently, the type Meramecian comprises only the upper Warsaw Shale, and Salem The age assignment of the Moorefield interval is and St. Louis Limestones (Lane and Brenckle 2005). complicated further by a proposal to reduce the This interval is zoned on conodonts, but the lithostratigraphic succession comprising the interval comprises only two zones: the Gnathodus Meramecian Series (Lane and Brenckle 2005), and a texanus zone, which spans the Osagean-Meramecian lack of ammonoid assemblages in its type area, St. boundary, and the Hindeodus scitulus and Louis County, Missouri. Lane and Brenckle (2005) Apatognathus scalenus zone, which appears in the placed the Osagean-Meramecian boundary at the middle St. Louis Limestone and extends to its contact
Journal of the Arkansas Academy of Science, Vol. 70, 2016 80 http://scholarworks.uark.edu/jaas/vol70/iss1/14 80 Journal of the Arkansas Academy of Science, Vol. 70 [2016], Art. 14 Age and Correlation of the Moorefield Shale (Upper Mississippian), Northeastern Arkansas
with the Gnathodus bilineatus zone in the succeeding Hall J. 1857. On the Carboniferous Limestones of the Ste. Genevieve Limestone (Lane and Brenckle 2005). Mississippi Valley. American Association for the Thus, the Meramecian Series has no lower boundary Advancement of Science Proceedings 10(2)51-69; defined by conodonts, and comprises essentially a also The American Journal of Science and Arts, single conodont zone. In comparison, the underlying second series, 23:187-203. Osagean Series and overlying Chesterian Series each Korn D and AL Titus. 2011. Goniatites Zone (middle comprise all or part of eight conodont zones (Lane and Mississippian) ammonoids of the Antler Foreland Brenckle 2005). The Meramecian Series must Basin (Nevada, Utah): Bulletin of Geosciences, represent only half the absolute time of either the Czech Geological Survey (Prague), 86(1):p. 107– preceding Osagean Series, or succeeding Chesterian 196. (60 figures, 37 tables, appendix). Series of the Mississippian Subsystem, and since 1983, Lane HR and PL Brenckle. 2005. Type Mississippian the duration of the Mississippian Subsystem has been subdivisions and biostratigraphic succession, in reduced to the current 35.7 my, a reduction of 4.7 my, Heckel, PH, (ed.), Stratigraphy and Biostratigraphy for the International Chronostratigraphic Chart (Cohen of the Mississippian Subsystem (Carboniferous et al. 2016). Although lacking precise absolute dates, System) in its type region, the Mississippi River the duration of the Meramecian would appear to be Valley of Illinois, Missouri and Iowa: more consistent with a stage, rather than a series. International Union of Geological Sciences, Subcommittee on Carboniferous Stratigraphy, Acknowledgements Field Conference, St. Louis, Missouri, September 8-13, 2005, Illinois State Geological Survey The Department of Geosciences, University of Guidebook 34:76-98. Arkansas, contributed the page charges for this paper. Owen DD.(assisted by W Elderhorst, and ET Cox). Devon Energy provided thesis support for Dalu. 1858. First Report of a Geological Reconnaissance of the Northern Counties of Arkansas made during Literature Cited the years 1857 and 1858: Arkansas Geological Survey, (Little Rock), 256 p. Adams GI (assisted by AH Purdue, and Owen DD. 1860. Second Report of a Geological EF Burchard). 1904. Zinc and Lead Deposits of Reconnaissance of the Middle and Southern Northern Arkansas with a section by E. O. Ulrich, Counties of Arkansas made during the years 1859 Determination and Correlation of Formations: U.S. and 1860: Arkansas Geological Survey Geological Survey, Professional Paper 24:1-89. (Philadelphia) 431 p. Cohen KM, SM Finney, PL Gibbard and JX Fan. Penrose RAF. 1891. Manganese: Its Uses, Ores and 2013 (updated 2016). The International Deposits: Geological Survey of Arkansas, Annual Commission on Stratigraphy: International Report for 1890. 1: 642 p. Chronostratigraphic Chart. Episodes 36:199-204. Saunders WB, WL Manger and M Gordon. 1977. Comstock TB. 1888. Report Upon the Geology of Upper Mississippian and Lower and Middle Western Central Arkansas, with especial reference Pennsylvanian ammonoid biostratigraphy of to gold and silver: Arkansas Geological Survey, northern Arkansas. In Sutherland, PK and Manger, Annual Report 1:1-320. WL (eds.), Upper Chesterian-Morrowan Drake NF. 1893. Report on the Colorado Coal Field of Stratigraphy and the Mississippian Pennsylvanian Texas, in ET Dumble, Fourth Annual Report of the Boundary in Northeastern Oklahoma and Geological Survey of Texas, 1892 (1):357-444. Northwestern Arkansas. Oklahoma Geological Girty GH. 1911. The Fauna of the Moorefield Shale of Survey, Guidebook 18:117-138. Arkansas: U. S. Geological Survey, Bulletin 439. Williams HS. 1895. On the Recurrence of Devonian 148 p., 15 pls. Fossils in Strata of Carboniferous Age. American rd Gordon M. 1944. Moorefield Formation and Ruddell Journal of Science, 3 Series. 49: 94-101. Shale, Batesville District, Arkansas: American Worthen AH. 1860. Remarks on the Discovery of a Association of Petroleum Geologists Bulletin Terrestrial Flora in the Mountain Limestone of 28(11):1626-1634. Illinois (abs). American Association for the Gordon M. 1965 [1964 imprint]. Carboniferous Advancement of Science Proceedings. 13:312-313. Cephalopods of Arkansas: U.S. Geological Survey, Worthen AH. 1866. Geology of Illinois. Geological Professional Paper 460. 322 p., 30 pls. Survey of Illinois. 1: 152 p. Journal of the Arkansas Academy of Science, Vol. 70, 2016 81 Published by Arkansas Academy of Science, 2016 81